Prenatal toxicology of shale oil retort water in mice

Shale oil retort water, a by-product of the production of oil from shale, potentially amounts to tens of millions of gallons per year and must be treated or recycled with regard for public health. Such retort water was given to 98 female ICR/DUB mice in their drinking water at concentrations of 0, 0.1, 0.3, and 1.0% for periods up to 203 d. Seven of 75 treated animals developed adenomalike lesions that were not seen in the control animals. These ranged from adenomas and an adenomatoid nodule in the lung to the rectal adenocarcinoma. Although the incidence of adenomalike lesions was not statistically significant, this appearance of neoplasia requires further investigation. Eighty-five animals became pregnant. The proportion of animals pregnant, weights of nonpregnant animals, weight gain during pregnancy, average fetal weight, number of live fetuses per liter, and proportion of male fetuses were unaffected by drinking retort water. Early and late fetal deaths and preimplantation losses were likewise unaffected, except for a significant increase in preimplantation losses in animals consuming 1.0% retort water. A variety of palatal defects were seen in treated animals, however, including single and multiple cleft palates and a defect, to our knowledge not previously reported, in which the posterior portion of one or both palatal shelves appeared not to have formed. The palatal defects, as a group, were dose-dependent and statistically significant.